Socket contact



' with the accompanying drawings.

United States Patent Ofifice Delaware Filed June 13, 1957, Ser. No. 665,557 3 Claims. (Cl. 339--25S) This invention relates to electrical apparatus and more particularly to electrical connectors of the type wherein electrical connections are made by interfitting plug and socket contacts.

One of the objects of the present invention is to provide a socket contact of novel construction for use in readily separable electrical connectors of the pin and socket type. Another object of the invention is to provide a socket contact which although small in size provides surer and more forceful electrical connection between the socket and the pin of a socket connector.

A further object is to provide a substantially rigid socket contact having pin-retaining and contact-making spring means associated therewith, the body of the socket contact and the spring means being of such construction that the spring means contacts the pin forcefully even though the contact and spring are of small size.

Another object is to provide a socket contact of the type indicated in which the socket contact and the pinretaining and contact-making spring means associated therewith are protected from damage even though a pin or probe should be inserted in the socket contact in marked misalignment therewith.

A still further object is to provide a novel socket contact assembly of the type described which has a long and effective operating life.

The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

FIG. 1 is a view in plan of one form of socket contact embodying the present invention, a male contact or pin, shown in phantom lines, cooperating therewith;

FIG. 2 is a longitudinal sectional view of the socket member, the section being taken generally on the line 2-2 of FIG. 1, certain parts being shown in elevation;

FIG. 3 is a longitudinal sectional view of the socket member, the view being similar to FIG. 2 except that a fragmentarily shown pin member is engaged in the socket contact;

FIG. 4 is a view in vertical transverse section taken generally along line 44 of FIG. 3;

FIG. 5 is an enlarged fragmentary view in plan of the socket member, the spring means being omitted therefrom;

FIG. 6 is a view in longitudinal axial section through the spring means of the socket contact prior to the assembly-of such spring means on the socket member;

FIG. 7 is a view in bottom plan of the spring means; and

FIG. 8 is a view in end elevation of such spring means, the view being taken in the direction from left to right in FIG. 6.

In the embodiment illustrated in the accompanying drawings, by way of example, the novel electrical socket contact of the invention includes only two partsa body or a socket member 10 and a contact spring 11. In the embodiment shown the body is made in the form of a rigid metallic bar suitably machined, as by drilling and 3,023,396 Patented Feb. 27, 1952 milling, in the manner to be described. The spring 11 is made of sheet metal, and is applied to member 10 in a permanent manner by fastening means which, in the contact shown, is integral with spring 11. The socket member is designed to receive a pin 16 of a plug member 12 so as to make secure, non-arcing contact, therewith, while permitting the ready separation of the pin and socket member by movement of the two axially away from each other.

Socket or body member 10 is preferably made from copper alloy bar stock which has been cold drawn after heat treatment. In one successful embodiment, the copper alloy consists of about 60% copper, .5 to 1% tin, .4 to 1% lead, .1% or less iron, and the remainder zinc. In another suitable embodiment the copper alloy consists of a minimum of 96.5% copper, .85 to 1.35% nickel, .15 to 35% phosphorous, .35 to .65% tellurium, a maximum of .2% iron, at maximum of .1% lead, and a maximum of 1% zinc.

Spring 11 is preferably formed from a blank cut in the form of a T from fully heat treated copper alloy sheet stock, such as Berylco #10 containing about .24 to 2.7% cobalt, .38 to .50% beryllium and the remainder copper. Another excellent non-magnetic metal from which spring 11 may be made is known commercially as Inconel. This is a high nickel alloy which need not be plated and which is less abrasive on the pin contact. Spring steel may also be used in making spring 11, if desired.

One end of body member 10 is drilled to provide a bore 14 for slidably receiving the pin 16 of the aforementioned plug member 12. The open end or mouth of bore 14 is preferably made bell-shaped at 15 to facilitate entry of pin 16, which has a diameter only slightly less, usually about .002 to .005", than the diameter of bore 14. The other end of member 10 is likewise drilled and partially cut away at one side to provide a suitable recess 17 in which the end of an electrical conductor may be secured by soldering or other suitable means. Intermediate its ends, member 10 is machined to form two annular grooves 19 and 20, the first of which is utilized in mounting the contact in a resilient support or insert, such as in the manner disclosed in Uline et al. US. Patent No. 2,563,762.

Groove 20 is utilized, in the manner to appear hereinafter, for mounting spring 11. Such spring has a main longitudinally extending finger 21, shown at the top in FIGS. 2 and 3, which extends from a position adjacent but spaced from the free end of body 10 rearwardly along the body to the groove 20 where it is provided with oppositely extending wings 22 which are bent to form a collar tightly fitting into groove 20. Preferably groove 20 has a radial depth substantially equal to the thickness of wings 22 so that the resulting collar lies flush with the main outer circumference of the socket. The finger 21 is substantially straight and lies substantially parallel to the longitudinal axis of body 10 throughout the portion of its length from the collar formed from wings 22 forwardly toward the free end of the finger. Finger 21 is of such width that substantially no portion thereof lies outwardly of the outer circumference of body 10 even when a pin 16 is received in bore 14.

As shown most clearly in FIGS. 6, 7, and 8, spring member 11 is provided with shallow flanges 24 which strengthen the finger against deflection in that portion adjacent the collar. In order that flanges 24 will not interfere with or bind upon body 10, such body is provided with a first transversely extending slot 25 which has a radial depth somewhat greater than flanges 24. In the embodiment shown, slot 25 is of such width axially of body 10 that its rear end extends partially into groove 20 and its forward end intersects the inner end of bore 14. Although such intersection of bore 14 by slot 25 is not necessary in carrying out the invention, such construction is preferred since it allows bore 14 readily to be cleaned of foreign matter as by the application of a blast of air to its outer end. Slot 25 eliminates any blind pocket which would otherwise interfere with the proper circulation of the plating solution when body It IS electroplated.

Forwardly of slot 25 body has a broad flatted portion 26 having an axial width substantially exceeding the diameter of bore 14. The flatted portion 26 is so positioned on body 19 that the central longitudinal zone of the flatted portion lies at a distance from the longitudinal axis of body 10 a distance substantially equalling the radius of groove 20. The wall of body it, at the flatted portion is of reduced thickness, as shown in FIGS. 2 and 3, but such thickness is sufiicient to give it adequate strength to resist deformation by a pin or probe upon the insertion or withdrawal of the latter. Thus, with the exception of the zone of the wall of the bore in the vicinity of the second or forward transverse slot 27, to be described, the socket provides an unbroken wall at the pin-receiving bore through the major extent of that portion thereof adjacent the open end of bore 14.

The above mentioned second transverse slot 27 is provided at the free end of body 10 immediately to the rear of the annular end portion 18 at the free end of the body. In the embodiment shown, slot 27 has a radial depth such that the edge surfaces 29 of the slot lie somewhat outwardly of the diameter of bore 14. Preferably also the slot is in the form of a truncated V in axial section to insure freedom of movement of the free end 30 of spring 11. As shown, the free end of the finger is downwardly and then upwardly bent to form a projection or dimple 30 on the finger. Finger 21 is of generally uniform width, in the embodiment shown the finger tapering slightly toward its free end. End 30 has a width somewhat greater than the distance between the inner edges of opposite surfaces 29 of slot 27, as shown in FIG. 4.

Body 10 is preferably formed on a screw machine, which among other initial operations, forms the grooves 19 and 20 and the bore 14. Following this, the body 10 is further shaped by a series of transverse cuts which form slot 25, flatted portion 26, and slot 27. Such further cuts may be formed simultaneously, if desired, by a milling machine employing one composite cutter. Spring 11 is preferably first blanked out of sheet stock, the blank then being bent into the contour shown in FIGS. 6, 7, and 8, wherein the wings 22 form the parallel legs of an inverted U, and the finger 21 is bent downwardly so that its free end 30 lies markedly below its root.

The spring 11 is applied to contact member 10 by wrapping the wings 22 on the former tightly around the body 10 within groove 20. If desired, the ends of wings 22 may be suitably secured together or said wings may be soldered, spot-welded, or similarly secured to body 10. After the spring member 11 has been thus applied to body 10, in the absence of a pin member in bore 14, the finger 21 is forcibly urged by its inherent springiness into the position shown in FIG. 2 where the finger overlies and at least substantially contacts the flatted portion 26 of body 10. In such position the depressed or dinipled portion 31 on the free end of the finger projects a substantial distance into bore 14, and the inner surface of portion 31 at least substantially contacts the bottom of slot 27. When a contact pin or plug such as pin 16 of plug 12 is inserted into bore 14, projection 31 on finger 21 will be engaged by the pin and finger 21 will be thus flexed outwardly, placing it under additional tension. The spring thus yieldably presses the pin 16 against the opposite wall of bore 14 to provide good electrical connection. The pressure exerted on the contact pin by the spring is so predetermined that it will never be too easy all or too difficult to engage and disengage the pin and socket contacts. The present construction is such that the force required to engage a pin with the socket or disengage it therefrom will remain reasonably constant during long periods of use. The greater breadth of finger 21, and the strengthening thereof adjacent the root by flanges 24, insure satisfactory spring pressure even though the pin and socket assembly may be quite small in size. The engagement or substantial engagement between the main extent of finger 21 and of flatted portion 26, as well as the reception of projection 31 in slot 27, effectively maintains finger 11 from unwanted turning of the one relative to the other. The provision of a bore 14 which is unbroken for a major part of its length in the entering end thereof, except for groove 27 which is substantially elfectively closed by projection 31, insures that neither the socket member nor the spring will be fouled or damaged by carelessly applied contact pins or probes.

There is thus provided an electrical socket assembly which is highly efficient in effecting a good electrical connection and which is exceptionally durable in use under the most severe adverse conditions. The assembly is also advantageously made of only two parts of simple construction, such parts being readily and inexpensively made and assembled in a manner which will insure the desired engaging and disengaging force.

Although only a single embodiment of the invention has been illustrated in the drawings by way of example, it is to be expressly understood that various changes, such as in the relative dimensions of the parts, the materials used and the like, may be made therein without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art.

What is claimed is:

1. An electrical socket contact comprising an elongated cylindrical metallic body having an axial cylindrical bore in one end and terminating short of the other end, an elongated external axially extending flatted zone in the wall of the socket contact around said bore, said flatted zone extending from a position adjacent the open end of the bore to a location remote therefrom, a first transversely extending slot in said flatted zone adjacent the open end of said bore and extending into said bore, a contact retainer comprising an elongated generally straight resilient finger having a generally fiat inner face closely overlying and confronting said flatted zone, the finger having a width generally the same as the width of the flatted zone, and a length which is generally the same as the length of the bore, means rigidly to secure a first inner end of the finger to the socket body at a location adjacent but inwardly beyond the inner end of said zone, means on the free end of the finger which projects into the path of the bore when no pin is in the same, the finger being normally under tension urging the free end portion thereof inwardly toward the axis of the bore and the finger into contact with said flatted zone, a second transversely extending slot in said flatted zone adjacent the root of the finger and lying radially inwardly of and beneath the finger, and wherein the finger is secured to the socket body by a collar integral with the finger, and comprising finger-reinforcing formations located along the respective side edges of the finger at the root thereof, the formations overlying and being partially received in said second transverse slot.

2. An electrical socket contact comprising an elongated cylindrical metallic body having an axial cylindrical bore in one end and terminating short of the other end, an elongated external axially extending fiatted zone in the wall of the socket contact around said bore, said flatted zone extending completely across the body, said flatted zone extending from a position adjacent the open end of said bore to a location remote therefrom, a first transversely extending slot in said flatted portion adjacent the open end of said bore and extending into said bore, a second transversely extending slot in said flatted portion and extending into at least the end of said bore, a contact retainer comprising an elongated resilient finger having a generally fiat inner face overlying and confronting the flatted zone of the body, the finger having a width which is at least a large fraction of the width of the flatted zone and a length which is generally the same as the length of the bore, means rigid to secure the root end of the finger to the socket at a location remote from the open end of the bore, said last named means comprising a collar integral with the finger, the other free end of the finger lying adjacent and beyond the end of the flatted zone at the open end of the bore, finger-reinforcing formations located along the respective side edges of the finger at the root thereof, the formations overlying and being partially received in said second transverse slot, and means on the free end of the finger to project into the path of. the bore when no pin is in the bore, the finger being normally under tension urging the free end portion thereof inwardly toward the axis of the bore.

3. An electrical socket contact comprising an elongated cylindrical metallic body having an axial cylindrical bore in one end and terminating short of the other end, an elongated external axially extending flatted zone in the wall of the socket contact around said bore, said flatted zone extending completely across the body, said flatted zone extending from a position adjacent the open end of said bore to a location remote therefrom, a first transversely extending slot in said flatted portion adjacent the open end of said bore and extending into said bore, a second transversely extending slot in said flatted portion and extending into at least the end of said bore, a contact retainer comprising an elongated resilient finger having a generally fiat inner face overlying and confronting the flatted zone of the body, the finger having a width which is generally the same as the width of the flatted zone and a length which is generally the same as the length of the bore, an annular groove in the body rearwardly of the flatted zone, the radius of the inner surface of the annular groove being substantially equal to the radius of the central longitudinal portion of the flatted zone, means including a broad collar securely mounted within the annular groove rigidly to secure the root end of the finger to the socket, the other free end of the finger lying adjacent and beyond the end of the flatted zone at the open end of the bore, and means on the free end of the finger to project into the path of the bore when no pin is in the bore, the finger being normally under tension urging the free end portion thereof inwardly toward the axis of the bore.

References Cited in the file of this patent UNITED STATES PATENTS 2,410,098 Muller Oct. 29, 1946 2,427,182 Bergan Sept. 9, 1947 2,715,215 Flora Aug. 9, 1955 2,716,744 Swanson et al. Aug. 30, 1955 FOREIGN PATENTS 206,628 Great Britain Nov. 15, 1923 

